The present invention relates generally to metallurgy, and more particularly to a method for metallurgically attaching together two members.
Resistance welding (also known as electric-resistance welding) is a known metallurgical process wherein metal is heated by its own resistance to a semi-fused or fused state by the passage of very heavy electric currents for very short lengths of time and then welded by the application of pressure.
Conventional methods for metallurgically attaching together two parts also include a known method for metallurgically attaching together an inlet/outlet tube to a vehicle fuel tank cover. In the known method, a sheet-metal plate of low-carbon steel is obtained for the vehicle fuel tank cover, and a low-carbon steel tube is obtained for the inlet/outlet tube. A through hole is punched in the plate creating a flange which surrounds the through hole and which projects longitudinally away from the plate. Forming operations on the tube create a transversely-projecting annular rim on the tube. The tube is sized so that it is insertable in the through hole so as to longitudinally extend beyond both longitudinal ends of the through hole. The tube is inserted in the through hole so that the rim of the tube is seated on the plate and the flange of the plate projects away from the rim. Then, the tube and the plate are brazed together near the through hole.
For the brazing operation, a furnace is required having specific temperatures and temperature gradients. The furnace must be kept with a controlled reducing atmosphere to remove the oxides from the plate and the tube before the brazing is actually performed. Also, a copper ring must be used for the filler material to perform the brazing. A ceramic chain pulley mechanism is required to move the parts through the furnace.
What is needed is a less expensive method for metallurgically attaching together two members, such as metallurgically attaching together an inlet/outlet tube to a vehicle fuel tank cover.
A first method of the invention is for metallurgically attaching together two members. The method includes steps a) through d). Step a) includes obtaining a first member having a through hole with a longitudinal axis and first and second longitudinal ends and having a longitudinally-projecting flange surrounding the through hole. Step b) includes obtaining a second member having a transversely-projecting annular rim. Step c) includes, after steps a) and b), at least partially disposing the second member in the through hole of the first member with the flange of the first member projecting away from the rim of the second member. Step d) includes, after step c), resistance welding together the first and second members so as to create a weld, wherein after the weld is created, the rim of the second member is seated on the first member at the first longitudinal end of the through hole.
In one application of the first method, the first member is a plate, such as a vehicle fuel tank cover, and the second member is a tube, such as an inlet/outlet tube. In one implementation, step d) creates a resistance weld between the flange of the plate and the tube. In another implementation, step d) creates a resistance weld between the plate and the rim of the tube. In an additional implementation, step d) first creates a resistance weld between the flange of the plate and the tube and then creates a resistance weld between the plate and the rim of the tube.
An other method of the invention is for metallurgically attaching together two members. The other method includes steps a) through d). Step a) includes obtaining a first member having a through hole with a longitudinal axis and first and second longitudinal ends and having a longitudinally-projecting flange surrounding the through hole. Step b) includes obtaining a second member. Step c) includes, after steps a) and b), at least partially disposing the second member in the through hole of the first member. Step d) includes, after step c), resistance welding together the first and second members so as to create a weld.
In one application of the other method, the first member is a plate, such as a vehicle fuel tank cover, and the second member is a tube, such as an inlet/outlet tube. The other method is useful when it is desired only to create a resistance weld between the flange of the plate and the tube, and for this weld, as can be appreciated by the artisan, the tube does not require a rim.
Several benefits and advantages are derived from the invention. Resistance welding is less expensive than brazing. In the application for metallurgically attaching together a vehicle fuel tank cover and an inlet/outlet tube, instead of costing about one dollar per attachment it is expected to cost only a few cents per attachment.